P1441

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The evaporative system includes the following components:

^ The fuel tank

^ The EVAP vent solenoid

^ The fuel tank pressure sensor

^ The fuel pipes and hoses

^ The vapor lines

^ The fuel cap

^ The evaporative emission canister

^ The purge lines

^ The EVAP purge solenoid

The EVAP purge solenoid valve allows the manifold vacuum to purge the canister. The Vehicle Control Module (VCM) supplies a ground in order to energize the solenoid valve (purge ON). The EVAP purge solenoid control by the VCM is Pulse Width Modulated (PWM) or turned ON and OFF several times a second. The duty cycle (pulse width) is determined by the engine operating conditions including the load, the throttle position, the coolant temperature, and the ambient temperature. The duty cycle is calculated by the VCM, and the purge solenoid is commanded ON when certain conditions have been met.

The system checks for conditions that cause the EVAP system to purge continuously by commanding the EVAP vent solenoid ON and the EVAP purge solenoid OFF (EVAP vent solenoid CLOSED, EVAP purge PWM 0%). If the fuel tank pressure level increases during the test, a continuous purge flow condition is indicated. The following items can cause this condition:

^ A leaking EVAP purge solenoid

^ A grounded EVAP purge solenoid driver circuit

If any of these conditions are present, a DTC P1441 sets.

CONDITIONS FOR SETTING THE DTC

The following conditions will set the DTC:

^ No MAP sensor DTCs

^ No TP sensor DTCs

^ No VSS DTCs

^ No HO2S DTCs

^ No ECT DTCs

^ The DTC P0125 not active

^ No IAT sensor DTCs

^ The ECT is greater than 4°C (39°F) but less than 30°C (86°F).

^ The IAT is greater than 4°C (39°F) but less than 30°C (86°F).

^ Start up ECT is not more than 8.25°C or 14.85°F greater than the start up IAT

^ Start up IAT is not more than 1.5°C or 2.7°F greater than the start up ECT

^ The Fuel Level is between 12.5-87.5%.

^ The Baro is greater than 72.5 kPa.

^ The System Voltage is between 10-17 volts.

^ During the diagnostic test, the VCM detects a continuous open purge flow condition.

ACTION TAKEN WHEN THE DTC SETS

The VCM will turn ON the MIL after 2 consecutive driving cycles with the fault active.

CONDITIONS FOR CLEARING THE MIL/DTC

^ The VCM turns the MIL OFF after 3 consecutive drive trips when the test has Run and Passed and not Failed.

^ A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (coolant temperature has risen 22°C (40°F) from the startup coolant temperature and the engine coolant temperature exceeds 70°C (160°F) during the same ignition cycle).

^ Use the scan tool Clear Information function.

^ Disconnect the VCM battery feed for 30 seconds.

DIAGNOSTIC AIDS

Check for the following conditions:

^ A loose, missing, damaged, or improperly installed fuel cap

^ Missing or damaged O-rings at EVAP canister fuel vapor and purge line fittings

^ A cracked or punctured EVAP canister

^ A damaged or disconnected source vacuum line, EVAP purge line, vent hose or fuel tank vapor line

^ A poor connection at the VCM: Inspect the harness connectors for the following conditions:

- Backed out terminals

- Improper mating

- Broken locks

- Improperly formed or damaged terminals

- poor terminal to wire connection

^ A damaged harness: Inspect the wiring harness to the EVAP vent solenoid EVAP purge solenoid and the fuel tank pressure sensor for an intermittent open or short circuit

^ A kinked, pinched or plugged vacuum source, EVAP purge, or fuel tank vapor line. Verify that the lines are not restricted

Refer to EVAP System Cleaning before starting repairs.

Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.

TEST DESCRIPTION

The numbers below refer to the step numbers on the diagnostic table:

2. Determines if the EVAP Purge Solenoid is leaking.

3. Determines if the EVAP canister Purge Valve Driver circuit is shorted to ground.

4. Determines if the EVAP canister Purge Valve Driver circuit wiring or VCM is at fault.